This invention relates to a method of automatically testing the quality of transmission in a data transmission system in which, in the operational state and during data transmission based upon the established code, other bits are transmitted in addition to the data bits.
In data transmission, it is frequently necessary, when connections are being developed, to test the data transmission system for proper operation prior to data transmission or during a pause in transmission. It is already well known, in determining the quality of the transmission system to carry out distortion measurements or error rate measurements. However, this requires the use of test message transmitters and test message receivers or special pulse shapes have to be transmitted and evaluated. Whatever the case, the analysis of the transmission system necessitates an additional expense, and the operating conditions are not precisely adhered to. Where measurements of quality are concerned, the presence of an operator at the station located at the other end of the link is necessary, this in order to switch in the items of equipment required for carrying out the measurements and to transmit back resultant measurements to the station carrying out the measuring.
An object of this invention is to provide a method of testing the transmission quality in a data transmission system, which enables the entire system to be tested automatically while in service.